<template>
  <!-- 商品分类导航 -->
  <div class="type-nav">
    <div class="container">
      <!-- 事件委托|事件代理 -->
      <div @mouseleave="leaveChange" @mouseenter="getShow">
        <h2 class="all">全部商品分类</h2>
        <transition name="sort">
          <div
            class="sort"
            v-show="show"
            :style="{display:show==true?'':'none'}"
          >
            <div class="all-sort-list2" @click="goSearch">
              <div
                class="item"
                v-for="(c1, index) in categoryList"
                :key="c1.categoryId"
                :class="{ changeColor: currentIndex === index }"
              >
                <h3 @mouseenter="changeIndex(index)">
                  <a
                    :data-categoryName="c1.categoryName"
                    :data-category1Id="c1.categoryId"
                    >{{ c1.categoryName }}</a
                  >
                </h3>
                <!-- 
                二三级分类  
                方式一：:style="{display:currentIndex===index ?'block':'none'}"
                方式二：v-show item-list元素隐藏 v-show="currentIndex === index"
                -->
                <div class="item-list clearfix" v-show="currentIndex === index">
                  <div
                    class="subitem"
                    v-for="(c2, index) in c1.categoryChild"
                    :key="c2.categoryId"
                  >
                    <dl class="fore">
                      <dt>
                        <a
                          :data-categoryName="c2.categoryName"
                          :data-category2Id="c2.categoryId"
                          >{{ c2.categoryName }}</a
                        >
                      </dt>
                      <dd>
                        <em
                          v-for="(c3, index) in c2.categoryChild"
                          :key="c3.categoryId"
                        >
                          <a
                            :data-categoryName="c3.categoryName"
                            :data-category3Id="c3.categoryId"
                            >{{ c3.categoryName }}</a
                          >
                        </em>
                      </dd>
                    </dl>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </transition>
      </div>
      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import { mapState } from 'vuex'
// 全部功能引入
// import _ from 'lodash'
// 按需引入
import throttle from 'lodash/throttle'
export default {
  name: 'TypeNav',
  data() {
    return {
      // js控制背景色以及显示/隐藏
      currentIndex: -1,
      // 整个typeNav显示/隐藏
      show: true
    }
  },
  mounted() {
    if (this.$route.path != "/home") {
      this.show = false;
    }
  },
  computed: {
    ...mapState('home', ['categoryList'])
  },
  methods: {
    // 鼠标进入修改背景色回调
    // changeIndex(value) {
    //   this.currentIndex = value
    // },
    changeIndex: throttle(function (value) {
      this.currentIndex = value
    }, 50),
    // 鼠标离开回调
    leaveChange() {
      this.currentIndex = -1
      if (this.$route.path != "/home") {
      this.show = false;
    }
    },
    // 进行路由跳转回调
    goSearch(event) {
      // console.log(event);
      
      let node = event.target
      // 节点的dataset属性，可以获取节点的自定义属性与值
      let { categoryname, category1id, category2id, category3id } = node.dataset
      if (categoryname) {
        //准备路由跳转的参数对象
        let loction = { name: 'search' }
        let query = { categoryName: categoryname }
        //一定是a标签：一级目录
        if (category1id) {
          query.category1Id = category1id
          //一定是a标签：二级目录
        } else if (category2id) {
          query.category2Id = category2id
          //一定是a标签：三级目录
        } else {
          query.category3Id = category3id
        }
        //判断：如果路由跳转的时候，带有params参数，捎带脚传递过去
        if (this.$route.params) {
          loction.params = this.$route.params
          //动态给location配置对象添加query属性
          loction.query = query
          //路由跳转
          this.$router.push(loction)
        }
        this.show = false
      }
      
    },
    // 鼠标移入，展示分类
    getShow() {
      this.show = true
    }
  }
}
</script>

<style scoped lang="less">
.type-nav {
  border-bottom: 2px solid #e1251b;

  .container {
    width: 1200px;
    margin: 0 auto;
    display: flex;
    position: relative;

    .all {
      width: 210px;
      height: 45px;
      background-color: #e1251b;
      line-height: 45px;
      text-align: center;
      color: #fff;
      font-size: 14px;
      font-weight: bold;
    }

    .nav {
      a {
        height: 45px;
        margin: 0 22px;
        line-height: 45px;
        font-size: 16px;
        color: #333;
      }
    }

    .sort {
      position: absolute;
      left: 0;
      top: 45px;
      width: 210px;
      // height: 461px;
      // overflow: hidden;
      position: absolute;
      background: #fafafa;
      z-index: 999;

      .all-sort-list2 {
        overflow: hidden;
        width: 100%;
        height: 100%;
        .item {
          a {
            color: #333;
            cursor: pointer;
            &:hover {
              text-decoration: underline;
            }
          }
          h3 {
            line-height: 27px;
            font-size: 14px;
            font-weight: 400;
            overflow: hidden;
            padding: 0 20px;
            margin: 0;
          }
          .item-list {
            // display: none;
            position: absolute;
            width: 734px;
            min-height: 460px;
            background: #f7f7f7;
            left: 210px;
            border: 1px solid #ddd;
            top: 0;
            z-index: 9999 !important;
            -webkit-box-shadow: 2px 0 5px rgb(0 0 0 / 30%);
            box-shadow: 2px 0 5px rgb(0 0 0 / 30%);

            .subitem {
              float: left;
              width: 650px;
              padding: 0 4px 0 8px;

              dl {
                border-top: 1px solid #eee;
                padding: 6px 0;
                overflow: hidden;
                zoom: 1;

                &.fore {
                  border-top: 0;
                }

                dt {
                  float: left;
                  width: 54px;
                  line-height: 22px;
                  text-align: right;
                  padding: 3px 6px 0 0;
                  font-weight: 700;
                }

                dd {
                  float: left;
                  width: 415px;
                  padding: 3px 0 0;
                  overflow: hidden;

                  em {
                    float: left;
                    height: 14px;
                    line-height: 14px;
                    padding: 0 8px;
                    margin-top: 5px;
                    border-left: 1px solid #ccc;
                    a {
                      &:hover {
                        color: rgb(221, 37, 37);
                      }
                    }
                  }
                }
              }
            }
          }
        }
        .changeColor {
          background-color: #ddd;
        }
      }
    }
    // 过度动画样式
    // 进入的起点、离开的终点
    .sort-enter,
    .sort-leave-to {
      height: 0;
      transform: translateY(0px);
    }
    // 进入的终点、离开的起点
    .sort-enter-to,
    .sort-leave {
      height: 461px;
    }
    // 定义动画时间、速率
    .sort-enter-active {
      transition: all 0.5s linear;
    }
  }
}
</style>
